package com.gc.common.util;
import java.security.MessageDigest;

/**
 * MD5加密工具类
 * @author 章瑱彬 
 * 电话：15914921094
 * QQ：562800930
 * @since 2014年9月19日
 */
public class NewMD5Util {
    private final static String[] hexDigits = {"0", "1", "2", "3", "4",    
        "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};    
        
    /** * 把inputString加密     */    
    public static String generatePassword(String inputString){    
        return encodeByMD5(inputString);    
    }


    public static boolean validatePassword(String password, String inputString) {
        return password.equals(encodeByMD5(inputString));
    }    
    public static String returnEncodeByMde(String originString){  
        return encodeByMD5(originString);  
    }  
    /**  对字符串进行MD5加密     */    
    private static String encodeByMD5(String originString){    
        if (originString != null){    
            try{    
                MessageDigest md = MessageDigest.getInstance("MD5");    
                //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算    
                byte[] results = md.digest(originString.getBytes());    
                //将得到的字节数组变成字符串返回    
                String resultString = byteArrayToHexString(results);    
                String pass =  resultString.toUpperCase();    
                return pass;  
            } catch(Exception ex){    
                ex.printStackTrace();    
            }    
        }    
        return null;    
    }    
        
    
    private static String byteArrayToHexString(byte[] b){    
        StringBuffer resultSb = new StringBuffer();    
        for (int i = 0; i < b.length; i++){    
            resultSb.append(byteToHexString(b[i]));    
        }    
        return resultSb.toString();    
    }    
        
    /** 将一个字节转化成十六进制形式的字符串     */    
    private static String byteToHexString(byte b){    
        int n = b;    
        if (n < 0)    
            n = 256 + n;    
        int d1 = n / 16;    
        int d2 = n % 16;    
        return hexDigits[d1] + hexDigits[d2];    
    }    
      
    public static void main(String[] args){  
                 String pwd1="123";    
                 String pwd2="";    
                 System.out.println("未加密的密码:"+pwd1);    
                 //将123加密    
                 pwd2 = generatePassword(pwd1);    
                 System.out.println("加密后的密码:"+pwd2);    
                     
                 System.out.print("验证密码是否下确:");    
                 if(validatePassword(pwd2, pwd1)) {    
                     System.out.println("正确");    
                 }    
                 else {    
                     System.out.println("错误");    
                 }    
    }  
}
